<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
   *{
     margin:0;
     padding: 0;
     color: black;
 }
 #parrent{
     width:300px;
     height:150px;
     margin-top: 20px;
     background:teal;
     padding: 20px;
     overflow: hidden;
     border: 1px solid transparent;
 }
 #box1{
     position: absolute;
     float: left;
     width:100px;
     height:100px;
     background:aqua;
     margin:100px 0;
 }
</style>
<body>
    <div id="parrent">
        <div id="box1">
        我是box1
        </div>
        我是内容
    </div>
</body>

</html>